Look at hotels.com, which in many ways is comparable. It has around 1000 employees (one thousand). From wikipedia:

Hotels.com has 85 websites in 34 languages, and lists over 325,000 hotels in approximately 19,000 locations.

Going back to your comments, you could rephrase some of the earlier comments as: why on earth would you need millisecond performance improvements for a website/product listing rentals?